PCB Grounding Structure for Coated Display Module Covers
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Solution Overview
Problem
Conventional display devices with coated module covers experience deteriorated grounding performance due to the insulation coating, leading to increased electromagnetic interference (EMI) and additional costs, complexity, and reliability issues when using separate conductive tapes for grounding.
Innovation Solution
A display device design that incorporates a restriction member to ground the PCB to the module cover, utilizing a side bracket restricted by the module cover's coating layer, which ensures effective grounding without the need for additional conductive materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a liquid crystal display device is turned off, then power consumption is reduced, but the liquid crystal maintains its twisted structure causing residual images to remain
Solution Approach 1:
The patent applies periodic action by switching the liquid crystal display between different states (normal operation and inverted state) in alternating intervals. When the display is turned off, the liquid crystal molecules are periodically inverted every few seconds to prevent residual image formation, while still maintaining low power consumption state. This periodic switching allows the display to eliminate residual images without requiring continuous power consumption.
Solution Approach 2:
The patent changes the physical state parameter of the liquid crystal by inverting its molecular orientation. By applying a specific inversion voltage that reverses the twisted structure of the liquid crystal molecules, the display transforms the liquid crystal from its normal state to an inverted state, thereby eliminating residual images while maintaining power savings during the off period.
2Reliability
If an inversion voltage is applied to eliminate residual images, then residual images are removed, but display uniformity deteriorates due to voltage non-uniformity across the display
Solution Approach 1:
The patent introduces an intermediary component - the inversion voltage application mechanism with specific electrode configurations - to mediate the voltage distribution across the liquid crystal layer. By designing the electrode structure and voltage application method to compensate for inherent voltage non-uniformities, the system achieves uniform liquid crystal inversion across the entire display area, thereby maintaining display uniformity while effectively removing residual images.
3Reliability
If the liquid crystal is inverted to prevent residual images, then residual images are eliminated, but response time increases due to the additional inversion process
Solution Approach 1:
The patent implements periodic inversion action where the liquid crystal is inverted only during off periods at specific intervals, rather than continuously or on every state change. This periodic approach allows the liquid crystal sufficient time to complete the inversion process without unnecessarily increasing response time during active display periods, thereby balancing residual image prevention with acceptable response performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces EMI by ensuring proper grounding of the PCB, improves the reliability and uniformity of the grounding, reduces manufacturing costs and complexity, and enhances the design and safety of the display device.
Implementation Method 1
a liquid crystal layer which blocks light in an initial state in which no voltage is applied across the liquid crystal layer and allows light to pass through when a voltage is applied across the liquid crystal layer
Implementation Method 2
a first electrode and a second electrode which generate, when a voltage is applied thereacross, a field extending along a first direction across the liquid crystal layer
Data Source
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AI summary
A display device according to an embodiment of the present disclosure may include a display panel; a module cover disposed on the rear side of the display panel; a PCB mounted on the rear surface of the module cover; a side bracket connected to a side of the PCB and restricted by the rear surface of the module cover; and a restriction member restricting the PCB and the side bracket to the module cover and grounding the PCB to the module cover. The restriction member may include a head portion which is in contact with the PCB and restricts the side bracket; and a fastening portion extending from the head portion and fastened to the module cover.